Android adds a border to a view

foreword

Every time I add an ImageView, I find that there is a discrepancy between the width and height I set and the width and height I want. After researching, I find that it is actually because the picture still has a certain distance of inner margin, which leads me to need a 100x100 picture. It looks only 60x60. So how can I easily see the actual size of this picture, so I thought, it’s not enough to add a border to the picture

accomplish

drawable——Create a new resource file as a background image

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle"
    >
    <!--圆角边框-->
    <!--
    <corners android:radius="15dp" />-->
    <!--虚线-->
    <!--<stroke android:width="1dp"
        android:color="#000000"
        android:dashWidth="5dp"
        android:dashGap="2dp"
        />-->
    <stroke android:width="1dp"
        android:color="#000000"/>
    <padding
        android:left="8dp"
        android:top="8dp"
        android:right="8dp"
        android:bottom="8dp"
        />
</shape>

Then on the picture that needs to be set as a border, just reference the background to this file

example

layout file

 ...
<ImageView
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@drawable/level_fragment_shadow"
            android:background="@drawable/test_border"
            />
...

Implementation diagram: